[ConstraintSystem] Increase impact of implicit value-to-value conversion
[ConstraintSystem] Increase impact of implicit value-to-value conversion

This makes it possible to pick `CGFloat` function/operator overloads even
in the presence of literals, otherwise non-default literal score gets in
a way and solver ends up producing a lot more solutions with implicit
Double<->CGFloat conversion than it can disambiguate, so it's better to
just preserve the old behavior and pick `CGFloat` concrete overloads when
appropriate.

JGiola/swift,parkera/swift,xwu/swift,ahoppen/swift,tkremenek/swift,ahoppen/swift,JGiola/swift,atrick/swift,atrick/swift,tkremenek/swift,roambotics/swift,rudkx/swift,benlangmuir/swift,benlangmuir/swift,apple/swift,ahoppen/swift,xwu/swift,hooman/swift,tkremenek/swift,atrick/swift,roambotics/swift,ahoppen/swift,tkremenek/swift,gregomni/swift,hooman/swift,parkera/swift,rudkx/swift,parkera/swift,gregomni/swift,JGiola/swift,roambotics/swift,glessard/swift,glessard/swift,glessard/swift,tkremenek/swift,atrick/swift,parkera/swift,benlangmuir/swift,xwu/swift,rudkx/swift,roambotics/swift,gregomni/swift,parkera/swift,rudkx/swift,atrick/swift,benlangmuir/swift,ahoppen/swift,apple/swift,xwu/swift,rudkx/swift,parkera/swift,xwu/swift,apple/swift,ahoppen/swift,apple/swift,gregomni/swift,glessard/swift,hooman/swift,glessard/swift,hooman/swift,JGiola/swift,benlangmuir/swift,apple/swift,gregomni/swift,roambotics/swift,hooman/swift,hooman/swift,parkera/swift,roambotics/swift,tkremenek/swift,rudkx/swift,JGiola/swift,gregomni/swift,parkera/swift,apple/swift,benlangmuir/swift,xwu/swift,JGiola/swift,tkremenek/swift,atrick/swift,xwu/swift,glessard/swift,hooman/swift